Pretty much everybody, I think, agrees that some disputes are merely verbal. For example, I may overhear someone say "Derek has big hair," think of my colleague
Derek Ball, and retort, "you're wrong, Derek has short hair." If it turns out that my interlocutor was referring not to Derek Ball but to
Derek Parfit, then our dispute was merely verbal. She and I were talking past one another; "Derek" in her mouth meant something different than did "Derek" in mine, and it turned out we were both right in our respective claims about each "Derek." So much is pretty uncontroversial, I think. When one party says sentence S, expressing proposition p, and another party wrongly takes q to be expressed, and takes himself to disagree in arguing against q, we have a merely verbal dispute.
In some recent work, Dave Chalmers argues that the phenomenon of merely verbal disputes is broader than the example above suggests. He rejects the necessity direction of
A dispute over S is verbal iff the parties use S to express distinct propositions p and q (respectively) and the parties do not disagree over the truth of p or of ¬q.
His argument appears to be one involving intuitive counterexamples. I'm not convinced.